Ars Magica

The best thing about Ars Magica is the magic system. It also captures the flavour of Mythic Europe quite nicely.

Regions and Auras

The mundane world has other worlds layered on top of it. There are four other realms - the Divine, the Infernal, Faerie and Magic. An aura gives a place power in one of the realms. A church will have a Divine aura, a forest glade may have a Faerie aura. Creatures of that type gain a bonus, others gain a penalty.

A Region is a magical world that exists on the same place as the mundane world, but is different. A forest may have a Faerie forest existing alongside it, and those who have the right skills might be able to find the path to the Faerie forest.